Radiant tubes provide an indirect heat source for industrial furnaces and are particularly useful in heattreating furnaces filled with a protective gas atmosphere. The tubes isolate the products of combustion from the furnace interior and therefore from the workpiece. Combustion within the tubes provides the heat for radiation and typically extends over the entire tube length. Most radiant tube burners have been designed for use with gaseous fuel, and development of fuel oil burners has correspondingly lagged. Fuel oil radiant tube burners typically require high velocity combustion air to prevent tube failure caused by fast combustion of the fuel oil after injection into the tube. Unfortunately, this technique results in excessive operating noise, unstable combustion, uneven temperature distribution and inefficient fuel utilization.
Accordingly, it is an object of the present invention to provide a radiant tube burner capable of operation with either gaseous or liquid fuel.
Another object of this invention is to provide a radiant tube burner which produces a stable luminous flame over the entire length of the radiant tube. Correspondingly, an object of this invention is to provide even temperature distribution over the entire radiant tube length.
A further object of the present invention is to provide a radiant tube burner which operates quietly on liquid fuel.
Another object of the present invention is to provide a fuel efficient radiant tube burner.